We study the following natural variation on the classical universality problem: given an automaton M of some type (DFA/NFA/PDA), does there exist an integer l ≥ 0 such that Σl ⊆ L(M)? The case of an NFA was an open problem since 2009. Here, using a novel and deep construction, we prove that the problem is NEXPTIME-complete, and the smallest such l can be doubly exponential in the number of stat...

Universal/existential quantifiers can be seen as generalization of logical conjunction/disjunction. The universal (existential) quantification of an open proposition is the conjunction (disjunction) of all its possible instantiations. In other words, conjunction (disjunction) is a special kind of universal (existential) quantification where the domain of the variable is restricted to the set of...

A structure M is pregeometric if the algebraic closure is a pregeometry in all M ′ elementarily equivalent to M . We define a generalisation: structures with an existential matroid. The main examples are superstable groups of U-rank a power of ω and d-minimal expansion of fields. Ultraproducts of pregeometric structures expanding a field, while not pregeometric in general, do have an unique exi...

Background and Objectives: Infertility, particularly female infertility, can threat women's psychological health. Spiritual health can play a significant role in increasing people's abilities especially in tough conditions. The aim of this study was to investigate the effect of psychotherapy on existential health in infertile women. Methods: The study population of this experimental controlled...

Background: Nurses' direct exposure to COVID-19 patients and resulting health anxiety can threaten their performance of human and moral duties. Materials and Methods: This work was a descriptive correlational study. The statistical population was all nurses working in the intensive care unit of COVID-19 patients in Ardabil hospitals in the 2021 year, from which 150 people were selected by con...

We investigate the size of conjunctive query rewritings over OWL2QL ontologies of depth 1 and 2 by means of a new formalism, called hypergraph programs, for computing Boolean functions. Both positive and negative results are obtained. All conjunctive queries over ontologies of depth 1 have polynomial-size nonrecursive datalog rewritings; tree-shaped queries have polynomial-size positive existen...

Objectives:This study used a quasi-experimental method inthe pretest-posttest to evaluate the efficacy of cognitive-existential group therapy on hopefulness in parents of children with cancer. Methods:Thirty parents (24 to 54 years old) of children with cancer were divided randomly into experimental and control groups. Both groups were assessed with Miller Hope Scale (1988), as pre-test. The...